The problem you have is your smiths took on a job they just not that interested in doing for some reason. Perhaps work was slow when they agreed to do the job and easier work came along afterwards so your job keeps getting pushed back. Perhaps they a taking new jobs on for regular patrons and don't want to risk loosing regular jobs for your one of a kind. Only your smith knows.

Two years is too long. Face facts, another two years might still not see the job done. Ask for the return of your gun and any money you have paid and find another person to do the job. Some jobs can be done only if you find someone is willing and abel to do the job. Sounds like your smiths just can't get started much less finish your work. Sorry for the time you have spent waiting but life is too short.